Alignment method and a projection exposure apparatus using the same
US4952060A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 10, 1990 |
| Grant date | Aug 28, 1990 |
| Priority date | — |
| Expiry date | Jan 10, 2010 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F9/7084
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A projection exposure apparatus is disclosed for exposing a semiconductor wafer to a pattern, formed on a reticle, by projection using a projection lens system. The apparatus includes an alignment optical system disposed at a side of the wafer remote from the projection lens system. The alignment optical system is used to detect an alignment mark provided on the wafer, from the back of the wafer. In accordance with the detection, the wafer is moved so that its alignment mark is brought into a predetermined positional relation with the alignment optical system, whereby the reticle and the wafer are relatively aligned. With this arrangement, the wafer alignment mark can be detected without being adversely affected by a resist layer applied to the wafer surface. Thus, the reticle and the wafer can be aligned very accurately.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.